The field of the invention is chemical apparatus having tanks, and the present invention particularly relates to a method and apparatus for cushioning continuous exothermal reactions with, or in the presence of liquefied gases.
The state of the art of the present invention may be ascertained by reference to U.S. Pat. Nos. 3,636,331; 3,749,555; 3,793,258 and 3,794,471, and German Published Patent Application No. 2,032,700 of Georg Schroeder et al, having a publication date of Jan. 13, 1972 the disclosures of which are incorporated herein.
U.S. Pat. No. 3,793,259 discloses the state of the art of continuous bulk polymerization of vinyl chloride while the remaining references disclose the state of the art of continuous polymerization reactors.
When carrying out exothermal reactions, for instance polymerization reactions, uneveness in the reaction sequence or failure of heat exchange may force a resort to gas expansion from the reaction chamber as the only way to prevent the reactor from bursting.
Until recently, such exothermal reactions were carried out on a large scale in reactors containing about 20 cubic meters. When the pressure in such reactors became excessive, or when heat generation grew too large, the gases were expanded into a gas vessel at normal pressure or into the atmosphere. The quantities of escaping gas in the prior art are relatively minor and generally harmless through dilution into the atmosphere.
Such expansion into the atmosphere is impossible as regards the recently developed large reactors holding up to 200 cubic meters, as disclosed in German Published Application No. 2,032,700 because of ecological and safety hazards. Furthermore, appreciable amounts of input materials are lost in this manner. High costs eliminate the feasibility of catching the gases escaping from a reactor into a sufficiently large gas vessel under normal pressure.